DE102012006780B4 - Electromagnetic piston pump with piston sliding bearing, because of the pumping action of a directed drag flow - Google Patents

Abstract

By a solenoid (2) driven reciprocating pump (1) with a piston (9) which displaces the liquid and carries the armature piston (12) of the electromagnet (2) and in a cylinder (10) in a bearing with a plurality of storage zones , for example, with the storage zones (21), (22) and (23), is stored, wherein the electromagnet (2) from an electrical drive (36) is supplied with pulsating electrical energy, characterized in that at least the storage zones (22) and (23) are flushed with liquid by an additional pumping action is generated by the use of a drag flow for the liquid in the camp during a cyclic lifting movement of the piston (9), and that the liquid circumferentially from the adjacent to the third storage zone (23) Anchor space (4) is sucked and pumped back by suitable fluid-conducting channels (35) in the armature space (4) by the circulation grooves (33) in the central bearing zone (22) in the piston (9) by i Asymmetrically designed edges in a cyclic lifting movement of the piston (9) in the cylinder (10) produce a directed drag flow of liquid in the gap and thus a pumping action, the edges on the inlet side and outlet side different contours such as edge radii, chamfers or radii and bevels comprising composite form elements, and that the pulses of the electric current for supplying the electromagnet (2) have the same or different slopes of the rise and fall, which are tuned to an increase in the pumping action by the asymmetrical groove edges.

Description

The invention relates to a driven by an electromagnet reciprocating pump according to the preamble of the first claim.

By electromagnet driven reciprocating pumps for conveying and metering of fuel are known, for example from the DE 43 28 621 C2 and they have proven themselves. With the spread of fuels with a higher proportion of non-fossil substances such. As biodiesel or alcohols and thus also of water, the materials of the friction partners, in particular the piston and the cylinder had to be adjusted, yet set under certain operating conditions, new signs of wear in such metering pumps. The signs of wear are explained, for example, by local overheating in the case of localized lubricant failure or poorer lubricating properties in comparison to purely fossil media.

The pamphlets DE 10 42 382 A . EP 03 336 893 A1 . US Pat. No. 1,408,638 A , and DE 2 046 978 A show improved lubrication piston machines by advantageously shaped piston rings, grooves and lubricant supply channels. The publication DE 1 453 603 A shows a piston pump with a stepped piston, wherein a partial surface of the piston is used to supply the piston lubrication. From the pamphlets DE 10 2008 040 996 A1 and DE 10 2009 046 975 A1 as well as the document specified therein DE 103 60 601 A1 It is known that a hydraulic rod seal in a dynamic application can produce an asymmetrical drag flow.

Object of this invention is to pass through the storage area of the piston, a liquid stream, which cools the storage and any resulting decomposition or reaction products of the fuel and dissipates potential wear products. The dosing accuracy of the reciprocating pump should be maintained and the production costs should not increase significantly. The object is achieved by the characterizing features of the first claim, wherein the dependent claims make the solutions closer.

A driven by an electromagnet reciprocating pump includes at least one displacement chamber, two valves and a piston which is sealingly mounted in a cylinder and carries the armature piston of the electromagnet. The bearing of the piston is divided into three storage zones. For cooling the storage and for the removal of any resulting wear products at least the bearing gap of the central storage zone is increased, if necessary, the bearing gap of the armature chamber side storage zone is increased. The bearing gaps of the armature chamber side storage zone and the central storage zone are flowed through by liquid, which is conveyed by means of a directed drag flow from the piston in cooperation with other components of the reciprocating pump.

In a preferred embodiment, the first displacement-side bearing zone is formed by a bearing bush and the piston, a second bearing zone has an enlargement of the bearing gap, and a third bearing zone again has a smaller bearing clearance. The second storage zone is fluidly connected to the armature space via suitable channels. Asymmetrical shape elements on the circumferential grooves in the piston or in the cylinder, for example, different sized edge radii or different chamfers, cause in a cyclic stroke of the piston different strong Schleppströmungen in the gap depending on the direction of movement of the piston and thus give a directed pumping action on the liquid in the second storage zone. In this embodiment, the capacity of the reciprocating pump is not affected, because the additional promotion inside the pump takes place in a circle and is not effective to the outside. The promotion can be done from the anchor space in the second storage zone or vice versa, depending on the orientation of the asymmetric form elements.

In an advantageous further development of the reciprocating piston pump, the cylinder consists of a carrier and two bearing bushes, wherein the bearing clearances in the three bearing zones formed thereby have different sizes, a good seal for the first bearing bush, a good bearing capacity for the second bearing bush and a good pumping action to reach for the middle cylinder area.

In an alternative development of the reciprocating pump, the cylinder consists of a carrier and a bearing bush on which to the displacement chamber 3 adjacent end of the cylinder, wherein the bearing bush has a smaller bearing clearance to the piston than the carrier, so that a good seal is achieved.

In a further development of the reciprocating pump is one of the bushings or both bushings are accommodated for better cooling in the carrier in an interrupted bore, the liquid-filled interruption zone is connected by a fluid-conducting channel with an adjacent liquid-carrying space, whereby a fluid exchange is made possible.

The described embodiments are suitable for cooling the bearing gap between the piston and the cylinder and for removing any resulting wear products in the case of flushing.

• • drückendem oder ziehendem Anker,
• • einem oder zwei Verdrängerräumen
• • Förderung bei bestromtem Elektromagnet oder bei der Rückkehr des Ankers in die Ruhelage
• • Steuerung nur durch Rückschlagventile oder durch eine Kombination aus einem Rückschlagventil und einer hubabhängigen Schlitzsteuerung
• • einer Kombination eines Ventils zwischen den Verdrängerräumen mit einem Einlassventils oder mit einem Auslassventil.

The technical teaching for flushing and cooling of the bearing can be applied to reciprocating pumps of different types, preferably electromagnetically driven reciprocating pumps of the known types

• • pushing or pulling anchor,
• • one or two displacement rooms
• • Conveying when the electromagnet is energized or when the armature returns to its rest position
• • Control only by check valves or by a combination of a check valve and a stroke-dependent slot control
• • a combination of a valve between the displacement chambers with an inlet valve or with an outlet valve.

To operate the reciprocating pump, a controlled electrical voltage or a regulated electrical current for the electromagnet is used. The electrical supply has a pulse-shaped time course, the frequency determines the flow rate of the reciprocating pump, the pulse-pause ratio is matched to the pressure at the outlet of the pump, and the edge slopes of the pulses are matched to the requirements of the liquid flow in the storage , In this case, a large edge steepness can help to effect a rapid change of the liquid flow, and this is advantageous for the removal of wear products from the storage area. The above-described cyclically repeating course of the electrical voltage or the electric current may be superimposed on a higher-frequency pulse width modulation, which serves to control the electrical current, the demand-based reduction of electrical power and / or the formation of the flanks of the low-frequency pulses.

The two measures for generating and influencing an additional pumping action, the recirculating grooves with asymmetrical edges and the design of the electrical pulses with matched edge steepnesses can be combined in an advantageous manner so that their effects mutually reinforce each other.

Reciprocating pumps of the type described are used as metering pumps and as delivery pumps in fuel-powered auxiliary heaters, additional heaters and exhaust gas purification systems in vehicles.

Images:

1 shows the reciprocating pump of the first embodiment with asymmetric circulation grooves.

2 shows the time course of the electrical voltage and the electric current at a superposition of the working pulse with a higher-frequency pulse width modulation

Exemplary embodiment

The reciprocating pump 1 according to 1 is by an electromagnet 2 powered and contains one with a piston 9 which displaces the liquid and the anchor piston 12 of the electromagnet 2 wearing. He is in a cylinder for that 10 in a warehouse with three storage zones 21 . 22 and 23 stored. At least the storage zones 22 and 23 are flushed with the liquid by at a cyclic stroke of the piston 9 an additional pumping action is generated by utilizing a drag flow for the liquid in the bearing. The liquid is removed from the third storage zone 23 adjacent anchor space 4 aspirated and through suitable fluid-conducting channels in the armature space 4 pumped back, or sucked through the fluid-conducting channels and through the third storage zone 23 pumped back.

The circulation grooves 33 in the middle storage area 22 in the piston 9 or in the cylinder 10 generated by their asymmetrically executed edges during a cyclic lifting movement of the piston 9 in the cylinder 10 a directed drag flow of the liquid in the gap and thus a pumping action, wherein the edges have different edge radii, chamfers or formed from radii and chamfer form elements.

As in 1 represented, there is the cylinder 10 preferably from a carrier 30 and two bushings 31 and 32 , wherein the bearing clearance in the three storage zones are made different sizes to a good seal for the first bearing bush 31 , a good bearing capacity for the second bearing bush 32 and to achieve a good pumping action for the middle cylinder area. In an alternative embodiment, the cylinder exists 10 from a carrier 30 and a bearing bush 31 at the on the displacement space 3 adjacent end of the cylinder, with the bearing bush 31 a smaller bearing clearance to the piston than the carrier 30 , The bearing bushes 31 and 32 are in an advantageous embodiment in the carrier 30 taken up in an interrupted bore, the liquid-filled interruption zone 34 with the anchor room 4 or the displacement room 3 is connected, whereby a fluid exchange with the adjacent fluid-carrying spaces is made possible.

As 2 represents that of the electrical control 36 generated electrical voltage or the associated electric current to supply the electromagnet 2 a pulse-like cyclically repeating time course, the frequency determines the flow rate of the reciprocating pump, the pulse-pause ratio is matched to the pressure at the outlet of the reciprocating pump and the slopes of the rise or fall of the pulses on the optimal pumping action by the asymmetric Nutkanten are tuned. In 2 For example, only different slope steepnesses for the rise and fall are shown. The above-described cyclically repeating course of the electrical current or the electrical voltage is superimposed on a higher-frequency pulse width modulation, which serves to control the electrical current, the demand-based reduction of electrical power and / or the formation of the flanks of the low-frequency pulses.

LIST OF REFERENCE NUMBERS

1

reciprocating pump

2

electromagnet

3

displacer

4

armature space

9

piston

10

cylinder

12

anchor pistons

21

First storage zone

22

Second storage zone

23

Third storage zone

30

carrier

31

First bearing bush

32

Second bearing bush

33

circumferential groove

34

interruption zone

35

channel

36

Control (not shown)

Claims (5)

By an electromagnet ( 2 ) driven reciprocating pump ( 1 ) with a piston ( 9 ), which displaces the liquid and the anchor piston ( 12 ) of the electromagnet ( 2 ) and in a cylinder ( 10 ) in a warehouse with a plurality of storage zones, for example with the storage zones ( 21 ) 22 ) and ( 23 ), wherein the electromagnet ( 2 ) of an electrical control ( 36 ) is powered pulsately with electrical energy, characterized in that at least the storage zones ( 22 ) and ( 23 ) are flushed with liquid by (at a cyclic lifting movement of the piston ( 9 ) an additional pumping action is generated by the use of a drag flow for the liquid in the bearing, and in that the liquid circulates out of the to the third storage zone ( 23 ) adjacent anchor space ( 4 ) and sucked through suitable fluid-conducting channels ( 35 ) in the anchor space ( 4 ) is pumped back by the circulation grooves ( 33 ) in the middle storage zone ( 22 ) in the piston ( 9 ) by their asymmetrically executed edges during a cyclic lifting movement of the piston ( 9 ) in the cylinder ( 10 ) generate a directed drag flow of the fluid in the gap and thus a pumping action, wherein the edges on the inlet side and on the outlet side have different contours such as edge radii, bevels or radii and bevels composed of form elements, and that the pulses of the electric current for supplying the electromagnet ( 2 ) have equal or different slope and fall slopes, which are tuned to enhance the pumping action through the asymmetric groove edges. Reciprocating pump according to claim 1, characterized in that the cylinder ( 10 ) from a carrier ( 30 ) and two bushings ( 31 ) and ( 32 ), wherein the bearing clearances in the three bearing zones are made different sizes, in order to provide a good seal for the first bearing bush ( 31 ), a good bearing capacity for the second bearing bush ( 32 ) and to achieve a good pumping action for the middle cylinder area. Reciprocating pump according to claim 1, characterized in that the cylinder ( 10 ) from a carrier ( 30 ) and a bearing bush ( 31 ) at which to the displacement space ( 3 ) adjacent end of the cylinder, wherein the bearing bush ( 31 ) has a smaller bearing clearance to the piston than the carrier ( 30 ). Reciprocating pump according to one of claims 1 to 3, characterized in that the bearing bushes ( 31 ) and or ( 32 ) in the carrier ( 30 ) are received in an interrupted bore whose liquid-filled interruption zone ( 34 ) via fluid-conducting channels in each case with the armature space ( 4 ) or the displacement chamber ( 3 ), thereby allowing fluid exchange. Method for operating a reciprocating piston pump ( 1 ) according to claim 1, characterized in that the electrical voltage or the electric current for supplying the electromagnet ( 2 ) has a pulse-like cyclically repeating time course, wherein the frequency determines the flow rate of the reciprocating pump, the pulse-pause ratio is matched to the pressure at the outlet of the reciprocating pump and the edge slopes of the rise or fall of the pulses to an increase in the pumping effect the asymmetrical groove edges are tuned, wherein the superimposed on the cyclic repeating course of the electrical current or voltage described above is a higher-frequency pulse width modulation, which serves to control the electric current, the demand-based reduction of electrical power and / or the formation of the edges of the low-frequency pulses.

Images